Whistleblowing is defined as the disclosure by an individual to the public, or those in authority, of mismanagement, corruption, illegality or some other form of wrong-doing in the workplace.
'An Enemy of the People' was controversial when first staged
Long the stuff of drama plotlines, such disclosures can have far-reaching consequences.
Acclaimed Norwegian playwright Henrik Ibsen's 1882 play 'An Enemy of the People' told the story of a small-town whistleblower who found himself out of step with the wishes of the rest of the townsfolk.
While Ibsen's protagonist ends the play declared insane, whistleblowers have successfully brought about the downfall of both governments and companies.
So why whistleblow? Of all the justifications offered, raising concerns in the public interest is the most noble.
It was with this motivation in mind that, in 1998, the UK passed the Public Interest Disclosure Act, which afforded wide-ranging protections to whistleblowers.
The current case of undercover nurse Margaret Haywood has brought whistleblowers back into the news and highlighted those risks. In Ms Haywood's case, she was struck off for breaching patient confidentiality by taking part in secret filming for a Panorama programme in 2005.
The whistleblowers' supporting charity, Public Concern At Work, said despite the risks, whistleblowing does not always end badly for the individual who takes that step.
Here is a list of some other high-profile whistle-blowers, both in the UK and abroad, who have taken that high-risk step.
Mark Felt - 'Deep Throat' - coined the phrase "follow the money"
In 2005, more than 30 years after the Watergate scandal rocked Washington, Mark Felt confirmed that he was indeed the Federal Bureau of Investigation (FBI) agent, codenamed 'Deep Throat', whose whistleblowing eventually led to the resignation of US President Richard Nixon in 1974.
Following the discovery of a break-in at the Democratic National Committee offices in the Watergate complex in Washington in 1972, Mr Felt passed on information to the Washington Post that the White House knew of the break-in and subsequently tried to cover it up.
Despite endless speculation about the true identity of Deep Throat, the source remained a secret until Mr Felt came clean aged 92. His advanced years effectively lessened any potential repercussions as he was not formally punished. By 2005, the Watergate leak had also been relegated to not only the history books but also the bestsellers' racks and Hollywood by the time Mr Felt's true identity was revealed.
Sarah Tisdall's whistleblowing led to a prison sentence
In 1983, with controversy raging over the government's decision to base US cruise missiles in the UK, the defence minister Michael Heseltine and Prime Minister Margaret Thatcher decided to keep the missiles' arrival date a secret to minimise potential demonstrations.
A 23-year-old Foreign Office assistant, Sarah Tisdall, disagreed with the decision and anonymously sent a copy of the memo to the Guardian newspaper. The Guardian duly published the information.
The government took legal action and Tisdall's name was revealed. She was sentenced to 6-months imprisonment for breaking the Official Secrets Act and served just over half her time.
She was most recently known to be working for an ethical property firm in Bristol.
David Shayler gave information to the Mail on Sunday
David Shayler was an MI5 officer who spoke out about deficiencies in the British secret services. He claimed they were unaccountable and inefficient and cited a number of examples to back his statements - most notably that MI6 officers paid Libyan plotters to kill Libyan president Muammar Gaddafi in 1996.
Fearing arrest and prosecution under the Official Secrets Act, Shayler fled to France. Though arrested and imprisoned by the French authorities, extradition back to the UK was refused.
Shayler voluntarily returned to the UK in 2000 and was arrested. At his trial, Shayler claimed he had no other avenues open to air his concerns but was found guilty and sentenced to six-months in prison.
He has subsequently become a controversial figure on the 9/11 conspiracy speaking circuit.
Jeffrey Wigand's story was filmed as "The Insider" in 1999
Dr Jeffrey Wigand was a senior executive in the US tobacco industry who told CBS Television in 1996 that the tobacco industry knew about the dangers of smoking years before the information was put in the public domain.
Upon his disclosure, Dr Wigand was vilified by colleagues and was sued by his former employees. The resulting court case was eventually settled as part of a wider action which saw tobacco companies doing a deal with 40 separate state prosecuting attorneys.
Subsequently, Dr Wigand was praised for his actions and is now a prominent anti-smoking campaigner.
Sherron Watkins of Enron became a reluctant public figure
Sherron Watkins is just one of a number of people who have spoken out about corruption in US big business in the last decade.
Ms Watkins was a departmental vice-president of US energy company Enron, whose internal memo infamously raised the concern that, "I am incredibly nervous that we will implode in a wave of accounting scandals" - a statement soon found to be accurate in the extreme.
The Enron accounting scandal ultimately brought down a company that had claimed revenues of over $100 billion in the year before the accounting mismanagement came to light in 2001.
Though purists argue over whether she was a genuine whistleblower - her concerns only came to light at a later stage - Time magazine felt her disclosures were of sufficient public interest to award her a place as one of their prestigious 'People of the Year' for 2002.